Does dry yeast ever expire really?

[BarbarianBrewer]

I brewed a cream ale (Spotted Cow clone) this past weekend. I used a packet of Safale K-97 yeast that expired in July 2023. It had been stored in a dry, cool environment. I knew that it's ok to use dry yeast that is past expiration but, I still thought there might be some fall off in vitality. After 24 hours there was a 1" kruezen and the picture below is after 48 hours. So no drop off there. It make me wonder how many years past expiration can you use dry yeast and not have a poor result?

 

[HighVoltageMan!]

Dry yeast expire??!! Never!!!

Well maybe, that sh!+ is pretty tough.

 

[Ozarks Mountain Brewery]

only if it stinks when you open it, or it got mosture inside, other than that no

 

[HighVoltageMan!]

At the end of the world, there will 2 things still alive, cockroaches and dry yeast.

 

[dmtaylor]

I am a small batch brewer, typically brewing between 1-2 gallons. I've found out on several batches recently that when I used the remainder of an old partial pack of dry yeast (which I *thought* should last forever), the old yeast that was exposed to the elements for many months or years was in fact dead as a doornail after waiting >48 hours after pitching. Indeed, apparently oxygen or moisture or whatever are NOT acceptable conditions when opened packs are stored in the fridge for future use. Maybe they last for a few months, but NOT forever. Granted, my partial packs were several years old. But they did NOT last forever as I expected.

I have NOT had a problem using super expired packs that had never been opened and were still nitrogen-packed or vacuum sealed. Many unopened packs have taken off just fine even when like 5 or 6 years old.

 

[HighVoltageMan!]

apparently oxygen or moisture or whatever are NOT acceptable conditions when opened packs are stored in the fridge

I heard from several sources (can't remember which ones) that oxygen is horrible for dry yeast. In the refrigerator and in it's original packaging, it can last way past the expiration.

 

[Over The Cliff Brewing]

when I have dry yeast opened, I seal the package with tape, put in a zip lock bag and then in the fridge. That works for me.

 

[Ozarks Mountain Brewery]

Just use a baggie the purge the air, I do the same with all food

 

[philjohnwilliams]

I"m now tempted to use the pack of Belle Saison in my fridge that expired in 2016.

 

[Minbari]

Just use a baggie the purge the air, I do the same with all food

Vacu-seal here

 

[dmtaylor]

when I have dry yeast opened, I seal the package with tape, put in a zip lock bag and then in the fridge. That works for me.

So do I. But... it does not always work for me. YMMV

 

[dmtaylor]

I"m now tempted to use the pack of Belle Saison in my fridge that expired in 2016.

I'm sure it will be great. I just picked up a few packs seeing as how Belle has recently been discontinued. Even if it does dang-near permanently contaminate all my equipment. I recently shared 3 different saisons at the last homebrew club meeting. Guess how many batches were actually intentional saisons.

 

[NorthCoastBrewer]

Vacu-seal here

This is likely the safest of all options when working with partial sachets.

For the strains of Lallemand yeast that I use, the TDSs currently mention that "If the opened package is re-sealed under vacuum
immediately after opening, yeast can be stored below 4C° (39°F) until the indicated expiry date. "

For my 2.5 gal batches, I close it tightly, use a rubber band to secure it, toss it in the fridge, and use it in another batch within a couple of months. So far, no problems. But I do try to track "best by" and "open?" information for my batches.

 

[Donoroto]

Guess how many batches were actually intentional saisons.

Almost one?

 

[Bigbre04]

Vacu-seal here

this is the way.